Edward j



' UN ED STATES FPATENT "OFFICE.

EDWARD J.DE SMEDT, OF WASHINGTON, DISTRICT OF COLUMBIA.

BITUMINOUS CEMENT.

SPECIFICATION forming- .part of Letters Patent No. 236,995, dated January 25, 1881.

Application filed December 21. 1880. (No specimens.)

"To all whom it may concern Be it known'that I, EDWARD J. DE SMEDT,

*of the'city of Washington, District of Columbia, have invented certain new and useful Improvements in Bituminous Cements, used for paving andother purposes, of which the following is a specification. m

My invention has originated iu'the effort to cure a certain defect noticeable in that class of pavements'com-monly known as bituminousconcrete, or asphalt, or bituminous pavements, audit is directed chiefly to that end. It is, however, applicable generally to bituminous cements used not only for paving but for other purposes.

It is a well-established fact that the relatively quick destruction or deterioration of a bituminous pavement is due, input, to the evaporation of certain volatile hydrocarbons during the heat of summer, but'chiefly to the gradual oxidation of thebituminous substances used as the matrix, which after a certain time 'changes'the'nature of the matrix and produces, to a greater or less extent, disintegration. It is my object to prevent, after the pavement has once been laid, any appreciable change of this kind in the matrix.

Goal-tar products are much more subject to oxidation by atmospheric air and other natural influences than are the asphalt products; but the coal-tar products have certain qualities which asphalts do not possess, and which are also lacking in the residuum resulting from the distillation of petroleum, which residuum is also now employed in making asphaltic cements. These qualities are adhesiveness and great tensile strength, coupled with impermeability resulting from a lack of affinity for moisture, and they combine to render the coal-tarproducts a particularly valuable element in a bituminous cement. It becomes, therefore, a desideratum to so prepare these products, preliminarily to their use in a bituminous cement, that they shall not thereafter be liable to appree'fable evaporation or oxidation under the naturalinfluences to which the cement may be subjected during its period of use, and it is to this end that my invention is directed. j

My invention consists in subjecting the coaltar products obtained as a residuum by the disthereby obtain two results.

tillation of coal-tar, and called in the trade by various numbers-e. 9., No. 2, No. 4, and so on-while in a heated and melted condition, to the action of an oxidizing agent, or an agent which will readily give up its oxygen to the said products when brought in contact therewith. I prefer to maintain the heat at, say, about 300 Fahrenheit, inasmuch as l I bring the coaltar products to a condition in which they will more readily combine with the oxidizing agent to produce the reaction, and I at the same time drive off or evaporate from said products oils volatile under 200 Fahrenheit. Taking Washington city as an example, bituminous pavements are notheated by the summer-heat at any time beyond 160 Fahrenheit, and by driving off from the coal -tar products oils which become volatile under 200 Fahrenheit I remove therefrom the constituents which would otherwise be liable to evaporate from the pavement after it was laid.

The manner in which I proceed in order to carry out my invention is as follows: The proper coal-tar product is placed in suitable known apparatus, and is there heated to, say, about 300 Fahrenheit, at which temperature it is maintained for twenty-four hours, more or less, in order to drive 011' oils volatile under 200 Fahrenheit. I do not wish, however, to be understood as restricting myself to these figures. For instance, by maintaining the product a longer time at a somewhat lower temperature the same, or approximately the same, result might be obtained. During this process of evaporation I oxidize more or less completely the coal-tar product. This I do by adding to said product, in proper quantity, a substance which will readily give up its oxygen, of which substances there are manyfor instance, permanganate of potash, or prefe'rably permanganic acid (Mn O The agent, which we will suppose to be permauganie acid, either powdered or in solution, is added gradually and in small quantities, and is thoroughly stirred into theheated coal-tar product in order to insure a perfectmixture. The permanganic acid in contact with the. coal-tar product is transformed into sesquioxide of manganese (Mn O by the loss of four atoms of oxygen,

which combine with the coal-tar producg. In

IOC

my experience I have found 1e 1 0 1nd of per oxidize the material itself and leave it othermanganic acid to be a sufiici mt qnai tity tot wise unchanged.

the necessary oxidation t one ton of Hit coal The oxidized product herein described may 45 tar products before nann The '4 al-tn bitu be used, either alone or in conjunction with 5 men thus oxidized may be a lded in v: rio is other bituminous substances, not only for pavproportions to asphaltit pre iarat ons or re inn, but for roofing, coating iron. &c.

ments. It gives to them a .rre: t -r tenacity l remark, in conclusion, that I can use the and renders them, or ill. pavemei t i r oth u oxidized product herein described in combi- 5o compositionsinto which he utter, les lrittle nation with known oxygenated heavy hydro- I0 and less liable to be afl'teted by air or \llft r. carbon oils, whether with or without addi- I remark that it is not neeessary. nor pertional substances, in making a composition or I haps desirable, to entirely oxi lize the eon-tar cement for paving and other purposes. product. This would ap roxin ateittooolose y Ilavingdeseribed myinventiomwhatlclaim, 5

to an asphalt and wouli inn air its t a aei y and desire to secure by Letters Patent, isand tensile strength. I npr; 0th a pur] oses, 1. The hcreinbefore-described improvement and with a view to its use in pavements at d in the art of preparing coal-tar products for the like, it is only necessaryto carry ti it prouse in bitmninous cements or compositions for cess far enough to insure that there sl all be paving: and other purposes, which consists in 60 no appreciable oxidation duringthe lit .-liIIlU subjeetiing said products, while maintained in of the pavement. a heated condition, to the action of an oxidiz- Itis manifest, as has been hereinhetora their in; agent, substantially as specified. tioned,that,besii esper l ingannte otpot: s ior 2. The pro :ess of treating coal-tar products permanganio acit ,there are ither know su ifor pavii at d other purposes, which consists (5 stances which can a so lwusei ,soim-ol'wl e in inaintii Iil g said products ata temperature for instance. pie aeid i ll NOQ UIHL- If about .5 m Fahrenheit for about the period are preferable, or soon lcctunts, to per-main it time s ieiitied, and adding to and inter- 1 ganic acid. The sibstn ees referred to gin; minglinguitl said 1 roductswhilesoheated an up their oxygen 1i eely l the presence o he ixidizing guit, substantially as specified. 7o coal-tar products index the -on litions at no .i. The (Hill ized rial-tar product hereinbementioned, while they do not decompose or fore deser'bed.

exereiseadestrur 'reet'tut,a some:n-ids(si r1 4. The applieatioi and use, in the manuassulphuricmitrr and iron it: 2 eidsnlo, 1 o 1 nature of ituiniuoi s cements for paving and thematerial. ()t'tl each s lastni med,rhr u do ither ]llll|))SS, of e )al-tar products deprived 75 acid, for instance, ll its ooi ipo inds, Siltll us if their to re volatile oils and oxidized, subbichromate of po ash. exercises a drstruct re stantially as and i'orthe purposeshereinbefore effect upon the m iterial, a portion of its oxy: sett'orth. gen uniting with the carbon of t ie coal-tar to in testimony whereof I have hereunto set form carbonic acid, and another iortion of its my hand this 20th day of December. 1880. oxygen uniting with the hydrogen ot' the ooal- E. J. DE SMEDT. 4o tar to form water. In other words, it acts to i Witnesses: decompose the material and to unite with the E. A. DICK, 1 separate elements of the latter, and not to M. BAILEY. 

